Substrates or assemblies having indirectly laser-fused frits, and/or method of making the same

ABSTRACT

Certain example embodiments relate to substrates or assemblies having laser-fused frits, and/or methods of making the same. In certain example embodiments, a pattern is formed or written on a stock glass sheet by laser fusing frit material to the glass sheet. An optional thin film coating is disposed on and supported by the stock glass sheet. The stock glass sheet with the pattern and the optional thin film coating is cut prior to heat treatment (e.g., heat strengthening and/or thermal tempering). A YAG or other type of laser source may be used to directly or indirectly heat the frit material, which may be wet applied to the substrate. In certain instances, the laser firing of the frit raises the temperature of the glass substrate to no more than 100 degrees C. and, preferably, the temperature is kept even lower.

FIELD OF THE INVENTION

Certain example embodiments of this invention relate to patternedsubstrates, and/or methods of patterning substrates. More particularly,certain example embodiments of this invention relate to substrates orassemblies having laser-fused frits, and/or methods of making the same.In certain example embodiments, (1) a pattern is formed or written on astock glass sheet by laser fusing frit material to the glass sheet, (2)an optional thin film coating is disposed on and supported by the stockglass sheet, and (3) the stock glass sheet with the pattern and theoptional thin film coating is cut prior to heat treatment (e.g., heatstrengthening and/or thermal tempering).

BACKGROUND AND SUMMARY OF EXAMPLE EMBODIMENTS OF THE INVENTION

Ceramic frit patterns currently are applied to interior and exteriorglass surfaces using known silkscreen or inkjet processes. Theseprocesses typically require the entire glass system to be heated totemperatures above 500 degrees C. to fire the frit into the glass,creating a strong bond. The patterned glass optionally may be coatedwith a thin film coating over the ceramic frit pattern. The thuspatterned and optionally coated glass may be used monolithically orbuilt into an insulated glass (IG) unit. Typically, the surface that ispatterned and optionally coated is disposed on the second surface fromthe sun.

FIG. 1 is a flowchart illustrating a current process for silkscreenprinting a pattern on a substrate. As shown in FIG. 1, bulk glass isproduced or provided in step S102. This mother substrate is then cutinto appropriate sizes in step S104. The silkscreen pattern is thenapplied to the sized pieces in step S106, and the patterned cut piecesof glass are heat treated (e.g., heat strengthened or thermallytempered) in step S108. The high temperature process used to fire thefrit is commonly conducted during the heat treating, although this isnot always the case. A separate drying and/or firing process maysometimes be used; however, having separate high temperature processesfor firing the frit and for heat treating the patterned substrate may beundesirable from cost perspectives (e.g., in terms of equipment costs),as well as time perspectives (e.g., as delays may be caused by multiplehigh-temperature heating and subsequent cooling processes). Referringonce again to FIG. 1, an optional thin film coating is disposed on theheat treated pieces (e.g., via sputtering or the like) in step S110. Thecut, patterned, tempered, and optionally coated pieces may be usedmonolithically or built into an IG unit in step S112.

The inkjet process involves a similar flow to that described above inconnection with FIG. 1.

FIG. 2 is a plan view of a substrate 200 having an example frit pattern202 formed or written thereon. As is common, the cut, patterned,tempered, and optionally coated pieces may be used in a wide variety ofapplications including, for example, windows in commercial settingswhere some light blockage is desirable, vehicle windshields (e.g., at oraround the periphery of the windshield), in residential settings, etc.

The heat treatment (e.g., tempering) typically involves quenching. Aswill be appreciated, the heat treated products cannot be further cut orsized. Thus, in conventional process flows, as indicated above, thecutting must take place before the heat treatment. And to save on hightemperature process steps, the frit typically is fired together with theheat treatment as indicated above.

Unfortunately, the current process flow suffers from severalinefficiencies and further improvements are desirable. For example,silkscreen and inkjet printing processes are performed on the cutsubstrates, prior to heat treatment. By contrast, thin film depositionis performed after the heat treatment, e.g., to help ensure thesurvivability of the coating. The patterning and thin film coating ofcut sheets, however, introduces inefficiencies as compared to patterningand coating the large, stock sheets of glass. Yield may be reduced, andpatterning and/or coating processes may be complicated by the need todeal with multiple different sizes of cut glass substrates.

Thus, it will be appreciated that there is a need in the art forimproved techniques for applying frit patterns to substrates.

Certain example embodiments of this invention relate to a method ofmaking a coated article. A frit material is applied to a glass substrate(e.g., via a suitable wet technique). The frit material is selectivelyfired via a laser source (e.g., a solid state laser such as a YAG laser)so as to form or write a predetermined pattern, wherein a laser from thelaser source directly or indirectly (e.g., through a or the substrate)contacts the frit material. Non-fired frit material is removed from theglass substrate (e.g., via washing). The glass substrate is cutfollowing said removing in making the coated article. The cut coatedarticle may be heat treated in certain example embodiments. In certainexample embodiments, a thin film coating may be deposited, directly orindirectly, on the substrate prior to said cutting.

Certain example embodiments of this invention relate to a method ofmaking an insulated glass (IG) unit is provided. A second substrate ispositioned in substantially parallel, spaced apart relation to theabove-described or other coated article made. A spacer is providedbetween the coated article and the second substrate. In certain exampleembodiments, where a thin film coating is provided, the coating may belocated on surface 2 of the IG unit.

Certain example embodiments of this invention relate to a heat treatablecoated article, comprising: a first glass substrate; a laser-fired fritmaterial formed or written on the substrate in a predetermined pattern;and a heat treatable sputter-, PVD- or CVD-deposited coating formed overthe substrate and the laser-fired frit material. The visible lighttransmission in regions of the coated article with the patterned fritmaterial thereon is less than 25% post heat treatment in certain exampleembodiments. An IG unit incorporating the same or a similar coatedarticle may be provided in certain example embodiments.

Certain example embodiments of this invention relate to a laser heatingsystem. A conveyor system is provided. Laser firing means are providedfor laser heating frit material applied to a glass substrate, with thelaser firing means including a YAG laser source and being controllableto directly or indirectly (e.g., through a or the substrate) heat thefrit material without raising the substrate temperature above 50 degreesC. At least one processor is configured to control the laser firingmeans so as to form or write a predetermined pattern in the fritmaterial.

The features, aspects, advantages, and example embodiments describedherein may be combined to realize yet further embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features and advantages may be better and morecompletely understood by reference to the following detailed descriptionof exemplary illustrative embodiments in conjunction with the drawings,of which:

FIG. 1 is a flowchart illustrating a current process for silkscreenprinting a pattern on a substrate;

FIG. 2 is a plan view of a substrate having an example frit patternformed or written thereon;

FIG. 3 is a flowchart illustrating an improved process for forming orwriting a frit pattern on a substrate in accordance with certain exampleembodiments;

FIG. 4 is a flowchart illustrating an example laser firing process inaccordance with certain example embodiments;

FIG. 5 is a schematic view of a laser directly heating frit material informing or writing a pattern in accordance with certain exampleembodiments;

FIG. 6 is a schematic view of a laser indirectly heating frit materialin forming or writing a pattern in accordance with certain exampleembodiments;

FIG. 7 is an illustrative coated article including a laser fused fritpattern in accordance with certain example embodiments; and

FIG. 8 is an illustrative insulated glass (IG) unit having anillustrative coated article including a laser fused frit pattern inaccordance with certain example embodiments.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

Certain example embodiments relate to substrates or assemblies havinglaser-fused frits, and/or methods of making the same. In certain exampleembodiments, (1) a pattern is formed or written on a stock glass sheetby laser fusing frit material to the glass sheet, (2) an optional thinfilm coating is disposed on and supported by the stock glass sheet, and(3) the stock glass sheet with the pattern and the optional thin filmcoating is cut prior to heat treatment (e.g., heat strengthening and/orthermal tempering). The laser fusing technique is fast and need notnecessarily heat the entire substrate to the frit firing temperature. Inother words, the laser may selectively heat a ceramic frit on the glass,either directly or indirectly. Thus, in certain example embodiments, alaser focused on the surface of the frit may help to fuse it to theglass without having to thermally treat the entire glass system. Theglass substrate with the frit pattern thereon may still be in theannealed state and thus may still be cut. The patterned glass may or maynot be coated with a thin film coating prior to heat treatment. Largesheets of patterned glass with the coating on the substrate (andpossibly over the pattern) may be cut to custom sizes, then heattreated, and used monolithically or in an insulated glass unit.

Referring now more particularly to the drawings in which like numeralsindicate like parts throughout the several views, FIG. 3 is a flowchartillustrating an improved process for forming or writing a frit patternon a substrate in accordance with certain example embodiments. Similarto as shown in FIG. 1, in FIG. 3, bulk glass is produced or provided instep S302. A frit pattern is then formed or written in step S304,example details of which are provided below. In step S306, a thin filmcoating that is capable of surviving the heat treatment process may beapplied over the substrate and over the frit pattern. In certain exampleembodiments, however, the thin film coating may be disposed over thesubstrate and the frit pattern may be disposed over the thin filmcoating. The mother glass substrate may be cut or sized in step S308 andforwarded on for heat treatment (e.g., heat strengthening or tempering)in step S210. The resulting substrates may be used in monolithicapplications or, in the alternative, they may be built into IG units instep S312. It will be appreciated that a monolithic article may beforwarded to a different party, e.g., for IG unit fabrication, incertain example embodiments.

FIG. 4 is a flowchart illustrating an example laser firing process inaccordance with certain example embodiments. As shown in FIG. 4, in stepS402, frit material is applied over the substrate. The frit may beapplied to the substrate by any suitable means including wet techniquessuch as, for example, curtain coating, roll coating, spin coating,coating via a Mayer rod, etc. The frit material may be applied to theentire, substantially the entire, or only portions of the substrate,depending on the desired end product. Masks optionally may be used tohelp control where the frit material is applied.

The frit material may be applied to a suitable thickness such that adesired opacity or transparency is obtained at the end of the process.It will be appreciated that the relationships between the thicknessinitially put down, the final thickness, opacity/transparency, etc., mayvary based on the frit material. Example frit materials that are usablein connection with certain embodiments of this invention include theLMC98 frit commercially available from TherMark, CerMark type fits,frits produced by Ferro, etc. A final thickness of 50-100 microns, morepreferably 60-90 microns, and sometime around 77 microns is suitable forthe LMC98 frit for various commercial applications.

The frit material, once applied, may be dried or allowed to dry in stepS404. Many frit materials will dry in about 10 minutes at roomtemperature. However, if faster dry times are desired, heat may beapplied. For instance, a temperature of 250-450 degrees F., morepreferably 300-400 degrees F., and sometimes around 356 degrees F. mayhelp speed the drying process.

The frit material may be laser fired in step S406 so as to help ensurethat it is fused, welded, or otherwise attached to the glass substrate.Any suitable laser may be used in certain example embodiments. It hasbeen observed, however, that solid state (e.g., YAG) lasers areparticularly advantageous as compared to other types of lasers(including, for example, CO₂ lasers). A 20 watt YAG laser at 100% powermay be used. When a YAG laser is used, a wavelength of between about1.03-2.0 microns may be used. In certain example embodiments, a 1064 nmwavelength operating at a frequency of 100 kHz may be used. The YAGlaser wavelength has been found to be advantageous in certain exampleimplementations, e.g., compared to CO₂ lasers, as YAG lasers have beenfound to provide better consistency and CO₂ lasers have been observed asoperating at wavelengths that damage the underlying glass substrate. Alinear speed of 40″/second is possible using a 20 watt YAG laseroperating at 100% power. However, it is possible to move to a higherwattage lasers (e.g., a 50 watt laser, etc.) in different embodiments,e.g., to increase speed.

A strike distance of 1/1000th of an inch is possible using a YAG laserand has been found to provide the desired opacity. The pattern may bepredetermined and stored to a non-transitory computer storage medium,readable by at least one processor of a laser control system. The lasermay be controlled via the control system so as to create thepredetermined pattern.

If the frit is water soluble, the excess material (e.g., where the fritis not fused by virtue of laser exposure) may be washed off in stepS408. Mechanical brushing or other means may be provided in addition orin the alternative in different embodiments of this invention.

FIG. 5 is a schematic view of a laser directly heating frit material informing or writing a pattern in accordance with certain exampleembodiments, and FIG. 6 is a schematic view of a laser indirectlyheating frit material in forming or writing a pattern in accordance withcertain example embodiments. The coated frit material 502 is supportedby the glass substrate 504. The laser source 506 emits a laser 508 wherethe frit material is to be patterned, creating a selective laser heatingarea 510. FIGS. 5 and 6 are similar to one another, except that thelaser directly laser heats the frit 502 in FIG. 5 and indirectly laserheats the frit 502 in FIG. 6. That is, in the FIG. 5 example, the lasersource 506 and the laser 508 are provided on the same side of thesubstrate 504 as the frit 502. By contrast, in the FIG. 6 example, thelaser source 506 is provided on a side of the substrate 504 opposite tothe frit 502, and the laser 508 extends through the substrate 504.

In one or both arrangements, there is no intentional heating of thesubstrate. Rather, the frit itself is heated to a suitable firingtemperature (e.g., typically around 650 degrees C. for many commerciallyavailable frits). The frits of certain example embodiments may be heatedup to the glass softening point, e.g., up to about 725 degrees C.depending on the type of underlying substrate used, in certain exampleembodiments of this invention. With the direct laser heating method inFIG. 5, the glass temperature is raised to a temperature less than 50degrees C. The indirect laser heating method of FIG. 6 may raise theglass temperature somewhat higher than in the FIG. 5 example; however,the temperature of the glass preferably remains less than 100 degrees C.and likely somewhere in the 50-100 degree C. range. In both cases,however, the glass can be safely handled by humans immediately after thelaser heating.

It surprisingly and unexpectedly has been found that indirect heatingmethods such as those shown in FIG. 6 provide better results than thosein FIG. 5. For instance, it has been found that the indirect heating inFIG. 6 enables a lower opacity to be obtained. One example direct laserheating application provided 25-30% visible transmission, whereas oneexample indirect laser heating application provided 19% visibletransmission.

The resolution is “sharper,” e.g., as measured at the edges of thepattern. It is believed that the direct heating techniques of FIG. 5involve patterning a more three-dimensional surface, whereas theindirect heating techniques of FIG. 6 provide a more two-dimensional orplanar surface to be patterned, e.g., because the interface betweenglass surface and the frit is very smooth.

Although the laser sources are shown “above” the frit in the FIG. 5 andFIG. 6 examples, different arrangements are possible. For example, fordirect laser heating embodiments, the laser source may be located belowa conveyor on which the substrate travels, provided that the frit-sideis facing downward. The laser from the laser source may fire the fritaccording to the pattern via a window or gaps between the rollers. Anumber of different arrangements also are possible for indirect laserheating embodiments. For instance, the laser source may be providedbelow a conveyor, with the coating side up, and with the laser beingaimed between the rollers or through a gap or window. As another examplearrangement for indirect laser heating, the laser source may be providedabove the substrate with the frit side facing down (e.g., towards therollers). An optional removable glass or other substrate may be providedbetween the rollers and the frit material. This protective sheet may beremoved prior to washing, etc.

It will be appreciated that two or more lasers may be used in certainexample embodiments. The two or more lasers may be provided on a commonside of the substrate, e.g., so that each of the lasers directly heatsor indirectly heats the frit material. However, in certain exampleembodiments, two or more lasers may be provided, with at least one laserprovided on a first side of the substrate and with at least one laserprovided on the opposite side of the substrate. Thus, certain exampleembodiments may allow for simultaneous laser heating from above andbelow. Such simultaneous laser heating from above and below may incertain example instances be focused on the same areas or on differentareas, e.g., potentially allowing for both direct and/or indirectheating at the same time on the same or different areas.

FIG. 7 is an illustrative coated article including a laser fused fritpattern in accordance with certain example embodiments. FIG. 7 shows asubstrate 702 supporting a frit 704 that has been laser patterned. Athin-film coating 706 is provided over the substrate 702 and thepatterned frit 704. Although a single layer 706 is shown, it will beappreciated that single layer or multi-layer coatings may be provided.Such coatings may be sputter deposited, PVD deposited, CVD deposited,etc., and such coatings may be capable of surviving high temperatures inthe event that they are disposed before heat treatment. Of course, suchlayers also may be disposed after heat treatment in certain exampleembodiments. In certain example embodiments, the coatings may servelow-E, protective/durable, antimicrobial, anticondensation,antireflective, and/or other features. For example, the coating 706 maybe a SunGuard low-E coating, a DiamondGuard protective coating, aClimaGuard coating, a ShowerGuard coating, etc., e.g., as known andprovided by the assignee of the instant invention.

Example low-E and/or anticondensation coatings are described in, forexample, application Ser. Nos. 12/926,714; 12/923,082; 12/662,894;12/659,196; 12/385,234; 12/385,802; 12/461,792; 12/591,611; and12/654,594, the entire contents of which are hereby incorporated hereinby reference. Example protective coatings are described in, for example,application Ser. Nos. 12/662,077; 12/801,848; 12/923,775; 12/923,778;and 12/929,252, the entire contents of which are hereby incorporatedherein by reference. Example three-layer AR coatings also are disclosedin co-pending and commonly assigned application Ser. Nos. 12/923,146 and12/923,838, the entire contents of which are hereby incorporated hereinby reference. Example four-layer AR coatings also are disclosed inco-pending and commonly assigned application Ser. No. 12/929,481 (filedon Jan. 27, 2011 under atty. dkt. no. 3691-2239 and entitled “HEATTREATABLE FOUR LAYER ANTI-REFLECTION COATING”), which also isincorporated herein by reference. Example anti-bacterial and/oranti-fungal coatings are described in, for example, application Ser.Nos. 12/662,443 and 11/412,118, the entire contents of which are herebyincorporated herein by reference.

The FIG. 7 example may be suitable for monolithic applications. However,the FIG. 7 example coated article may be built into an IG unit incertain example instance. In that regard, FIG. 8 is an illustrativeinsulated glass (IG) unit having an illustrative coated articleincluding a laser fused frit pattern in accordance with certain exampleembodiments. The FIG. 7 example coated article is spaced apart from asecond substrate 802, and a gap 804 is formed therebetween. A spacer 806is provided at the periphery of the substrates and helps to maintain thefirst and second substrates 702 and 802 in substantially parallel,spaced apart relation to one another.

The coating 706 is shown on surface 2 of the IG unit (e.g., on an innersurface facing the gap 804 of the outer substrate 702 that is nearestthe sun). Additional thin film coatings may be provided, for example, onother surfaces of the IG unit in different example embodiments.

It will be appreciated that the example coated article shown in FIG. 7also may be used in vacuum insulated glass (VIG) units in certainexample embodiments of this invention.

Although the end applications vary, typical silkscreen printing provides15-20% visible transmission in the regions of frit application. Overallvisible light transmission may depend at least in part on the percentarea the frit covers. The techniques disclosed herein may be capable ofmeeting or approximating this range.

It will be appreciated that the techniques described herein may be usedto produce coated articles suitable for a wide variety of applicationsincluding, for example, windows in commercial settings where some lightblockage is desirable, vehicle windshields (e.g., at or around theperiphery of the windshield), in residential settings, etc. Although anexample pattern and an example shape for individual fired frit elementsare shown in FIG. 2 (e.g., as a “dot pattern”), other patterns, shapes,sizes, etc., may be used in different embodiments of this invention. Theexample frit materials described herein at least initially are white butare fired to darker or more opaque colors. However, differentembodiments' may involve frit materials with different starting and/orending colors.

Although certain example embodiments have been described in connectionwith glass substrates, the techniques described herein may apply withrespect to substrates made of other materials. Thus, while the glasssubstrates of certain example embodiments may be borosilicate glass,soda lima glass, or other forms of glass, other substrates such asplastic substrates, polymer substrates, etc., may benefit from theexample techniques described herein.

As used herein, the terms “on,” “supported by,” and the like should notbe interpreted to mean that two elements are directly adjacent to oneanother unless explicitly stated. In other words, a first layer may besaid to be “on” or “supported by” a second layer, even if there are oneor more layers therebetween.

While the invention has been described in connection with what ispresently considered to be the most practical and preferred embodiment,it is to be understood that the invention is not to be limited to thedisclosed embodiment, but on the contrary, is intended to cover variousmodifications and equivalent arrangements included within the spirit andscope of the appended claims.

1. A method of making a coated article, the method comprising: applyinga frit material to a first glass substrate; selectively firing the fritmaterial via a laser source so as to form or write a predeterminedpattern, wherein a laser from the laser source indirectly contacts thefrit material; removing non-fired frit material from the first glasssubstrate; and cutting the first glass substrate following said removingin making the coated article.
 2. The method of claim 1, furthercomprising heat treating the cut coated article.
 3. The method of claim2, further comprising depositing a thin film coating, directly orindirectly, on the first substrate prior to said cutting.
 4. The methodof claim 3, wherein the thin film coating is deposited over andcontacting the fired frit material.
 5. The method of claim 3, whereinthe depositing includes sputter-, PCD- or or CVD-deposition.
 6. Themethod of claim 5, wherein the thin film coating is a sputter-depositedmultilayer low-E coating.
 7. The method of claim 2, wherein the lasersource is a YAG laser source.
 8. The method of claim 7, wherein a secondsubstrate is provided over the frit material and on a side opposite thefirst substrate, and wherein the laser from the YAG laser source heatsthe frit material through the second glass substrate.
 9. The method ofclaim 7, wherein the laser from the YAG laser source heats the fritmaterial through the first glass substrate.
 10. The method of claim 2,further comprising drying the frit material and/or allowing the fritmaterial to dry prior to said selective firing.
 11. The method of claim2, wherein the non-fired frit material is removed from the first glasssubstrate via washing.
 12. The method of claim 1, wherein the selectivefiring raises the temperature of the first substrate to no more than 100degrees C.
 13. The method of claim 1, wherein the visible transmissionof the coated article with the patterned frit material thereon is lessthan 25%.
 14. The method of claim 12, wherein the visible transmissionof the coated article with the patterned frit material thereon is lessthan 20%.
 15. The method of claim 1, wherein the frit material iswet-applied to the first substrate.
 16. A method of making an insulatedglass (IG) unit, the method comprising: positioning a second substratein substantially parallel, spaced apart relation to a coated articlemade according to the method of claim 1; and providing a spacer betweenthe coated article and the second substrate.
 17. A method of making aninsulated glass (IG) unit, the method comprising: positioning a secondsubstrate in substantially parallel, spaced apart relation to a coatedarticle made according to the method of claim 4; and providing a spacerbetween the coated article and the second substrate, wherein the coatingis provided on surface 2 of the IG unit.
 18. A heat treatable coatedarticle, comprising: a first glass substrate; a laser-fired fritmaterial formed or written on the substrate in a predetermined pattern;and a heat treatable sputter-, PVD, or CVD-deposited coating formed overthe substrate and the laser-fired frit material, wherein the visibletransmission of the coated article with the patterned frit materialthereon is less than 25% post heat treatment.
 19. An insulated glass(IG) unit, comprising: a second glass substrate provided insubstantially parallel, spaced apart relation to the heat treatablecoated article of claim 18; and a spacer located between the heattreatable coated article and the second substrate, wherein the coatingis located on surface 2 of the IG unit.
 20. A laser heating system,comprising: a conveyor; laser firing means for laser heating fritmaterial applied to a glass substrate, the laser firing means includinga YAG laser source and being controllable to indirectly heat the fritmaterial without raising the substrate temperature above 50 degrees C.;and at least one processor configured to control the laser firing meansso as to form or write a predetermined pattern in the frit material.